MEAN SHIFT尺寸链在某车型尾灯优化中的应用

尾灯板的结构形式直接影响尾灯匹配,为了减少尾灯定位孔尺寸链,文章提出了一种考虑MEANSHIFT的尺寸链分析方法,在设计前期对尾灯板结构进行优化。以某车型尾灯板结构优化为例,通过尾灯安装定位孔位置分析出该设计存在的风险,针对风险,提出调整定位孔位置的解决办法,使新结构尾灯孔偏差低于原结构,通过现场验证,证明该方法可行。     

客车车架有限元分析及尺寸优化

以某客车车架为对象,利用HyperWorks建立了车架的有限元模型并对其进行了刚度和模态分析,在此基础上,以质量最小为目标,在不降低刚度和模态性能的前提下,对车架进行了尺寸优化。     

模糊综合评价在多学科优化设计变量选择中的应用

以灵敏度分析理论为基础,将模糊数学综合评判理论应用于多学科优化设计变量的选择与评价。以某集装箱船为例,在建立了包含静力学、模态分析和动力学的多学科优化时设计变量选择的模糊评判数学模型之后,综合考虑了应力、位移、固有频率、速度和加速度等参数对设计变量的影响。分析表明,该方法简便易行、结果可靠。     

超大断面隧道软弱破碎围岩台阶法施工过程力学效应规律研究

超大断面软弱围岩隧道施工过程中,采用台阶法施工方案容易引起大面积塌方,但是可以有效缩短施工工期,从安全性的角度出发,台阶法施工特别是作为台阶法核心问题的台阶高度选择值得进一步分析。依托兰渝铁路两水隧道,采用三维数值仿真手段,分别建立台阶高度取H/3,H/2,2H/3和最大宽度处模型,模拟了铁路隧道在极软弱围岩中采用台阶法施工选择不同台阶高度的施工过程,对比不同台阶高度下隧道的拱顶沉降、水平收敛和掌子面挤出变形,揭示了台阶法施工过程中围岩力学效应的演化规律,并最终得出最优台阶高度,为工程施工提供参考。     

求解合理拱轴线的加权能量方法

通过构造一种基于拱轴线变形能的多参数拱轴线优化方法,以处理控制参数较少的函数曲线难以使拱轴线与压力线重合的问题。该方法以加权能量函数作为优化目标,运用样条曲线逼近主拱圈压力线,并建立主拱圈位移影响矩阵来计算主拱圈的位移调整量。加权能量方法将各个单元的弯曲变形能总和作为优化目标,通过给予每个位置的单元弯曲变形能不同的加权系数来达到调整拱轴线上各点的弯矩分布的目的。算例分析说明求解的拱轴线坐标是合理的,应用平均加权和高斯加权方法可有效减少主拱圈弯矩。     

Multi‐objective highway alignment optimization using a genetic algorithm

The available highway alignment optimization algorithms use the total cost as the objective function. This is a single objective optimization process. In this process, travel‐time, vehicle operation accident earthwork land acquisition and pavement construction costs are the basic components of the total cost. This single objective highway alignment optimization process has limited capability in handling the cost components separately. Moreover, this process cannot yield a set of alternative solutions from a single run. This paper presents a multi‐objective approach to overcome these shortcomings. Some of the cost components of highway alignments are conflicting in nature. Minimizing some of them will yield a straighter alignment; whereas, minimizing others would make the alignment circuitous. Therefore, the goal of the multiobjective optimization approach is to handle the trade‐off amongst the highway alignment design objectives and present a set of near optimal solutions. The highway alignment objectives, i.e., cost functions, are not continuous in nature. Hence, a special genetic algorithm based multi‐objective optimization algorithm is suggested The proposed methodology is demonstrated via a case study at the end.     

Second best toll and capacity optimisation in networks: solution algorithm and policy implications

This paper looks at the first and second best jointly optimal toll and road capacity investment problems from both policy and technical oriented perspectives. On the technical side, the paper investigates the applicability of the constraint cutting algorithm for solving the second best problem under elastic demand which is formulated as a bilevel programming problem. The approach is shown to perform well despite several problems encountered by our previous work in Shepherd and Sumalee (Netw. Spat. Econ., 4(2): 161–179, 2004). The paper then applies the algorithm to a small sized network to investigate the policy implications of the first and second best cases. This policy analysis demonstrates that the joint first best structure is to invest in the most direct routes while reducing capacities elsewhere. Whilst unrealistic this acts as a useful benchmark. The results also show that certain second best policies can achieve a high proportion of the first best benefits while in general generating a revenue surplus. We also show that unless costs of capacity are known to be low then second best tolls will be affected and so should be analysed in conjunction with investments in the network.

BRT车站组的线路停靠组合优化模型

为了缓解公交车辆进入单车道快速公交(BRT)车站容易出现排队的问题,提出了BRT车站组的线路停靠组合优化模型。首先基于排队论推导出BRT车辆进站不发生排队的概率模型,然后以最小排队概率为目标,提出整个车站组的线路停靠混合整数规划模型,并针对该模型的求解分别给出了一种基于分布式并行搜索的全局最优解算法和一种基于贪心策略的次优解快速算法;最后通过算例计算出广州市某个典型BRT车站组的线路停靠最优方案,利用VISSIM软件对优化方案及现有方案进行了多次仿真。结果表明:所提出的方法能够有效缓解公交车辆的进站排队现象。     

汽车电子电气架构设计与优化

阐述汽车电子电气架构技术与发展趋势,设计与优化的指导思想、需求信息、所用工具和工作流程,以及两个标准的系统级电子电气架构。介绍汽车电子电气架构设计与优化的优点,对我国汽车行业研发该项技术提出建议。     

城市公交线网优化的线性模型

为了对现有公交线网进行优化,有效利用现有交通资源,解决城市交通问题,运用系统科学的思想,通过对城市公交线网优化的主要内容、优化原则、优化目标以及约束条件的分析,兼顾考虑乘客出行时间、公交线网密度和公交企业的利益以及公交线网的布局对整个城市的交通系统的影响,提出了优化目标的函数表达式及相应约束条件的数学表达式,建立了公交线网优化的线性模型,并给出了运用逐步筛选法对所提出的数学模型进行求解的方法。